Fire-escape



(No Medal.)

c. M. MITCHELL & E. SMALL.

FIRE ESCAPE.

Patented Oct. 1, 1889.

[WW/Zion- W6 N PETERS. PholmLithogr-nphon Wnhinglnn. D. C.

UNITED STATES PATENT FFICE.

CYRUS M. MITCHELL, OF NASHUA, AND GEORGE E. SMALL, OF HUDSON,

' NEW HAMPSHIRE.

Fl RE-ESCAPE.

SPECIFICATION forming part of Letters Patent No. 411,869, dated October1, 1889.

I Application filed June 13, 1889. Serial No. 314,108. (No model.)

To aZZ whom it may concern.-

Be it knownthat we, CYRUS M. MITCHELL and GEORGE E, SMALL, both citizensof the United States, the former residing at Nashua,

in the county of Hillsborough, State of New.

l-iaxnpshire, and the latter at Hudson, in the county of llillsboroughand State of New Hampshire, have invented certain new and usefulImprovements in Fire-Escapes; and we do hereby declare the following tobe a full, clear, and exact description of the invention, such as willenable others skilled in the art to which it appertains to make and usethe same.

Our invention relates to fire-escapes, upon which persons descend. on awire or other suitable rope suspended from an elevated point of aburning building to the ground; and its object is to simplify and rendermore certain the operation of the friction device by which the descentis controlled; and the invention consists in a channeled friction-block, through which the rope upon which the descent is effected and bywhich the block is suspended is rove, said block being of the peculiarconstruction hereinafter described and claimed.

In the accompanying drawings, Figure 1 represents a perspective View ofour invention as it appears when in use suspended from an elevatedpartof a building. Fig. 2 is an enlarged side elevation of the improvedfriction-block detached from the rope, and Fig. 3 is an edge View of thesame. Fig. at is a vertical central section in the line 0c of Fig. 3,and Fig. 5 is a section in the line y yof Fig. 2.

A in the drawings represents a hook or staple adapted to be fastened tothe window sill or other firm part of a building; ]3,awire or othersuitable rope looped or fastened upon this hook and of a length to reachto or nearly to the ground.

0 is a friction-block having the rope B rove upon it, as shown; and D isa body-suspending strap, of any suitable construction, connected to theblock and adapted to be fastened around the body of a man in any securemanner, as illustrated. The friction-block is best and most effectivewhen made of an oblong form, as shown, as a greater length of an A form,as shown.

loop or bend in. the rope is secured through such form. Through thelowerportion of this block a hole a, is formed, and the suspendingstrapD is passed through it and secured. The outer edge of the perforatedlower portion 0 of the block is of circular form, and this portion isgrooved, ithaving a channel I), which in transverse section is of nearlyThis channel 1') terminates in a transverse slot 1), formed above theovate-formed port-ion c and below two laterally-extended curved wings cc of the block. This slot Z) unites with two curved, oblique, orlaterally and upwardly divergent channels Z) which are formed betweenthe wings and a nearly V-shaped central head portion 0 of the block, asshown.

From an examination of the drawings, Fig. at, itwill be seen that therope 13 (indicated by dotted lines) has one of its ends passed, first,through the channel b then down across the slot Z), and in the channel12 around the ovate portion 0, up across the said slot Z9, and throughthe channel b and being thus roved the other or upper end of the rope isfastened to a building, as illustrated in Fig. l, and its lower endallowed to rest upon the ground. The suspendin g-strap D, being fastenedas before described, hangs down below the block and is adapted to befastened to the body of a person. The rope B may be kept on the block inthe groove by a crossloop As an equivalent of the block having anovate-shaped portion and a tapered head por tion, and with sloth betweensaid portions, a block having the central portion of the space orslot 1) filled in with a thin web of metal might be adopted, leaving theropechannel, as shown, otherwise unchanged.

In case of a fire a person in the building fastens the fire-escape tothe building, and then fastens himself to the fire-escape by the strapD; and when his weight is brought to bear upon the fire escape the blockwill gradually descend upon the rope, its too rapid descent beingcontrolled by the peculiar deflection of the rope from a straight lineto a nearly ovate shape or bend, as illustrated by the dotted lines inFig. 3, and also by the wedging-bind of the rope in the nearly A-sliapedchannel around the lower or major portion of the block. In case thedescent of the block should from any-cause be so rapid as to endangerthe safety of the person, or it is necessary for any other purpose tocheck its speed, this can be instantly done by the descending persongrasping the rope B and pulling down hard enough upon it to cause therope to bind and bite more firmly upon the top surface of wing c and inthe wedge or A shaped friction-channel from beginning to end, thisoperation augmenting the friction to a very great extent, orsufficiently to accomplish the main objectnamely, prevent a too rapiddescent of the person doseending.

From the aforegoing description it will be seen that by constructing thefriction-block of an oblong form, with a rope-entrance portion at top onone side of the central head portion 0 and a rope-exit passage at top onthe other side of said central head portion, and with a rope-channelextending from one of said passages to the other, outside the ovateportion of the block, a very large frictionsurface for the nearlyovate-shaped looped or bent portion of the rope is secured, and this,together with the wedge shape, transversely, of the channel, insures africtional contact and bind of the block upon the rope sufiicient forenabling a person, under ordinary circumstances, descending graduallyenough for safety, and when descent is not slow or gradual enough, by apull with the hand upon the rope on which the block is descending, in. aproper direction, an almost positive bite or bind of the block upon. therope, from the beginning to the end of the bend of the rope or along theentire channel of the block, can be produced, and thus the blockarrested or the speed of its descent slackened, as described. It will beapparent that the weight of the descending person keeps the block nearlyvertieal, and that the resistance of this weight and the purchase at thesuspending hook or staple will enable the descending person to draw therope more tightly upon the channeled surface of the block, and therebywedge it into thechannel and force the entire or nearly entire length ofthe looped portion or bend in contact with said-A-shaped channelsurfaceof the block, which action upon the rope prevents the block moving asfreely as when the hand is withdrawn and simply the indirect'travel ofthe rope and the weight only of the descending person are relied uponfor controlling the descent.

By providing two symmetrical wings at the upper end of the block therope may be rove upon the block on either side; but it is not absolutelynecessary that there be more than one wing as long as two passages areprovided through the block at its upper end that is, one passage on theright hand and the other on the left hand of the central head portion.

That we claim is v 1. In a fire-escape, a friction-block C, hav- .ing acurved lower portion with a groove in one or more win s as c 0 havin resacct-- ively, a grooved inner and upper surface, of a suspending-strapD,-applied to the lower end of the block, and a rope B, rove through theblock and adapted to be suspended from a fixed part of a building andtherefrom extend below the block, all substantially as described.

In testimony whereof we affix our signatures in presence of twowitnesses.

CYRUS M. MITCHELL.

GEO. E. SMALL.

\Vitnesses:

R. T. SMITH, B. B. WHITTEMORE.

